Sewage screen



2 Sheets-Sheet 1 Oct. 21 1924.

E. E. JOHNSON SEWAGE SCREEN Filed Feb. 13. 1920 www? Oct. 21 1924. 1,512,028

E. E. JOHNSON SEWAGE SCREEN Filed Feb. 13. 1920 2 Sheets-Sheet 2 /v VEN TOR: 50W/ARD JH/vSo/v.

Patented Oct. 21, 1924.

UNITED STATES EDWARD E. JOHNSON, OF ST. lAUL, MINNESOTA.

SEWAGE SCREEN.

Application filed February 13, 1920. Serial No. 358,448.

T @ZZ whom t may concern Be it known that I, EDWARD E. JOHNSON, a citizen of the United States, residing at St. Paul, in the county of Ramsey and State of Minnesota, have invented certain new and useful Improvements in Sewage Screens, of which the following is a specication.

My invention relates to sewage or water purification screens and an object is to provide a device of this character which may be readily constructed and installed and which will. be efficient in operation. An object in particular is to provide a screen having a grating and a comb which are adapted to be moved relatively to each other with the teeth of the comb extending through the spaces in the grating whereby clogging thereof is prevented.

The full objects and advantages of my invention will appear in connection with the detailed description thereof and the novel features embodied in my inventive idea will be particularly pointed out in the claims.

In the accompanying drawings, which illustrate the application of my invention in one form,- f

Fig. 1 is a view in vertical section on the line 1-1 of Fig. 2. Fig. 2 is a view in vertical section on the line 22 of Fig. 1. Fig. 3 is an enlarged detail view in vertical section through the grating and comb, the section through the grating being on the line 3 3 of Fig. 1 with the comb moved into this position. Fig. 4 is a section on the line v4 4 of Fig. 3. Fig. 5 is a fragmentary sectional elevational view showing the manner in which the comb is cleaned. Fig. 6 is a detailed view showing the attachment of the upper ends of the comb teeth and omitting the grating.

Referring to the construction shown in the drawings, I provide a flume 10 preferably of concrete for conducting away the sewage after it has passed through a screen grating which removes the coarse material. The sewage is admitted above the grating by a pipe 12 and is maintained at about the level indicated at a by any customary or suitable means, as by a float valve of well-known construction which it is not necessary to illustrate for the purpose of explaining my invention. The screen is of concave or cradle form and is supported by curved longitudinal bars 14 which are held together by tie rods 16. Transverse bars 18 rest upon the curved bars 14, and as shown in Fig. 3

the transverse bars are received in notches in the curved bars. The grating which constitutes the screen proper is cylindrically curved for as much of the surface of a cylinder as desired and consists of a plurality of curved T-shaped members 20, as shown in Fig. 3, having their head portions arranged in curved alinement with each other and spaced slightly apart and having their stem portions resting in sockets vformed in the upper ends of a multiplicity of plates or lugs 22 the lower ends of which are secured in the transverse bars 18. The plates or lugs 22 have a width substantially equal to the thickness of the transverse bars 18 and said plates are preferably formed by doubling metal strips in the middle and offsetting the free ends to form the sockets for receiving the stems of the T bars, which may be secured in place by spot welding. The plates or lugs 22 are of sufficient height to support the whole of the T bars 2O above and free from the transverse bars 18 to provide clearance for comb teeth which will be described later. The spaces or slots 2Oa between the T bars are thus completely free longitudinally for the entire length of the T bars and in depth are free from the top of the T bars to the top of the transverse bars 18. The ends of the curved longitudinal bars 14 are supported upon angular bars 24 and thc sides of the cradle structure vare closed by plates 26. Rubber strips 28 resting upon the transverse bars 18 abut upon the plates 26 and provide a tight closure at the sides of the receiving basin which is formed above the grating. The inlet pipe 12 terminates adjacent a hole in one of the plates 26 and is screw-threaded'into a collar 30 bolted to the plate. Longitudinal angle bars 32 serve to support. a framework 34 which at its top has bearings 36 for a rock-shaft 38 to which is secured a crank arm 40 connected by a link 42 to a shorter crank arm 44. The latter crank arm is secured to a shaft 46 mounted in a bearing 48, and a belt pulley 50 is secured to the shaft 46 for rotating the same from any suitable source of power. The rock-shaft is positioned at the center of curvature of the screen and to this shaft are secured arms 52 having a bar 54 bolted to the lower ends thereof. This bar carries a comb which consists of teeth 56 between which are secured strips of rubber 58 which yieldingly support the teeth. The rubber strips are shorter than the teeth and the free the path thru which they are swept at each.

l'havey lpreferably considerable' widtl'i' as measured along' the slots 20i so' as to beA oiV suilieient strength to carry. the solidmatter w'hic'h they' collect' afs' theyv sweep forward;

They are Vpreferably formed with curved" edges shown'in-Figsz 1 e.. iifpp'lic-antl is' aware tliat certain' constructions 'have' been made for cleaning gratos or debrisv where a conibenters'and leaves grating slots ink its operation'. When however yit isy desired. to screen fine solids, greater i-'etiheinent off coni struction is necessary andin order t'o`y guardagainst4 wreckiiig'- the apparatus, do not` allow the cornb to leave the. slots-ini which operates. The operating connections' for tlie'f rock-slraft4 ar'e so proportioned and arranged that the comb is' giv'en an oscillatory movem'eiit' ed to end of the screen with tlie teeth of the c'ombf constantly' maintained in the; spaces betweenr the T These-teeth reiiiovelcoarse material which* willn'ot passV through the screen and oarry'it'lto one end or th'ei'othei` thereotand deposit' it introttghs or receptacles-60- The* activ'e or wet screen is that portion lyiiigj'below" the level @which is' kept well fbelow the ends 2()vc of' thescileeii Soas to leavedry the portions ofv the screen from 2ob to 20". The conib in its forward movement havingtraversed the wet portion of th'e screen carriesf'it's loadV of Solidsacr s the dry portion allowing anK appreciable draining thereof before these solids are eject# ed as will be later described. Inorder to clean the comb and facilitate tliezdeposit of the' coarse material iii* the trouglisth'e follow# ingv device is provided at" each' end of the screen. Brac'l'tets 62 areprovided withbears ings-*forv shaft 64 to w'liieliis sectire-d' belt pulley` oo'whieh is driven froment-"suitable sourceor power for'rotatingitheshaft. Se; cured" to saidsliaft are armsl o8 to' outer ends of',whichareY secured blades 70 of re'L v'olv'ingcleaner which nieve in proXiinityto the teethof the-comb when the latter is in its outward'position at the ends ofthe screen.

The operation and adventagesy of my' inventio' willV be readily' understood. from. the foregoing description. The einp-loyinentv of a plurality 'of T-bars having their head 'or'- tionsVV lplaced in l juxtaposition and sli@ lt-ly spacedfroin each other provides an e cient grating which may beY conveniently supported by ineens of the stein4 portions of the T- The lower edge 5er-of the comb teeth abextendsweilbelowthe-bottoni'edge-ofthe 'lf bar` grat'ing' asi shown in aind 4. The teeth of" the comb on accouito2 entendin'g through the spaces in the grating preventfc'loggingx notonily' by removing coarse material which lodges on top of the grating, btttl also by removing material which lodges in the spaces between the grating members. Sirio-e" theteet'li of tl'ieI comb are constantly maintained in the spaces between the grating members there is nol liability of' the teeth failing-J to 'cooperate properly Withthe' grating in' the spaces for which they are intend-VA ed'. The rubber strips `between lthe; teetl'iA permit lateral movement' of the latter so that' f they' ar'e readily' acconimodatedlto anv 'rre'gularitie-s'in the gratingvniernbers; TheK supl porting bars 14. are' notched at'tlieir ends as shown Fig'. l" to rest uponv the angle bars-j 2711i and hence' the gridA orfscreenY structure may bei' removed bodily for repairs. The hold the T-bars above and" awa-5;' ironithel cifossbars1 8y and allow slight" lateral movement oi" the T-bars toadjust. them tofthe* comb'A andto allow" the' teeth of the vcoi'n'b to' run completely between and' below the' mem; bers of the' grating in order to open up through grease which in some climatescoli lects' upon va'ndfbcl'ow thescr'e'en. surface. y

My screen is intended particularly` for use' as a sewage screen butit' vvi'llbe-l under; stood that'jitfis adapted for' general us'eas a water K purification screen.

l. A water purification screen comprising a grating, ya comb having teeth extending thru the slots in the grating, resilient 'mea-ns interposed between the base portions of said teeth, and meansl for' moving said.: grating and comb relatively" to each other *while`l oon.- staintly maintaining said teeth in saidislot's.

2. A water" purification screencompris? ing a cu'rved grating, ay rock-shaft positioned at the center of curvature of said grating, a

comb attached to said rock-shaft andl having teeth extending' thru the slots in said: Grat? ing', and means forl rocking; said to cause said comb tooscillate iz'rfoin end to end of said grating.

p 3. A water purificationl screen comprising y curved" grating, conib having teeth eat'en'ding thru the slots Ainsaid' grating, means for oscillating said comb froiii end to endlof Said' grating, and means at'theeiid'sof said l a curved grating, a Vcomb. havin teeth eX tending lthru the slots in the grating, means for oscillating said comb from end to end of said grating, receptacles at the ends of said grating, and rotatable members above said receptacles, said rotatable members having blades which sweep the comb when the latter is in its extreme outward positions.

6. A water purification screen comprising a curved grating, a comb having teeth extending thru the slots in said grating, resilient means interposed between the base portions of said teeth, and means for oscillating said comb from end to end of said grating.

7. A water purification screen comprising a curved grating having bars, curved supporting bars underneath said grating and concentric' with the bars thereof, and transverse bars extending between said grating and said supporting bars and resting upon the latter.

8. A water purification screen comprising a plurality of cylindrically curved T bars supported side by side and spaced from each other to form a grating having open ended slots, a comb having teeth extending thru the slots in said grating, and means for moving said grating and comb relatively to each other.

9. A water purification screen comprising a plurality of screen elements mounted in spaced parallel relation, outstanding lugs attached to said elements at intervals, and a plurality of transverse supports to which said lugs are fastened whereby said elements are supported as separate units.

10. A water purification screen comprising a grating made up of a plurality of screen elements mounted in spaced parallel relation to form slots extending the full length of the grating and open at both ends thereof, outstanding lugs attached to said elements at intervals, and a plurality vof transverse supports to which said lugs are fastened.

In testimony whereof I hereunto aiiix my signature.

EDVARD E. JOHNSON. 

